Rather, as Whedon says here, each director was not only allowed, but expected, to use their own voice and creativity.
While many have always assumed that the larger continuous story of the Marvel Cinematic Universe has always taken precedence over each individual movie, Joss Whedon, and the other directors involved in the roundtable, who include the Russo Brothers, Peyton Reed, Ryan Coogler, Jon Favreau, Taika Waititi, and James Gunn, insist that it’s not really the case.
James Gunn mentions that he was never asked to have Guardians of the Galaxy Vol. 2 end in any particular way for any particular character, simply that he gave the Russo Brothers an early copy of the script so that they would know where the characters were while incorporating them into Avengers: Infinity War.